document.write( "Question 1010649: A computer password consist of a letter of the alphabet followed by 3 or 4 digits.Find the total number of password that can be formed. Also find the number of passwords in which no digit repeats.
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Algebra.Com's Answer #626446 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "Digits can repeat:\r\n" );
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document.write( "Case 1.  1 letter followed by 3 digits\r\n" );
document.write( "Choose the letter 26 ways.\r\n" );
document.write( "Choose the first digit 10 ways.\r\n" );
document.write( "Choose the second digit 10 ways.\r\n" );
document.write( "Choose the third digit 10 ways.\r\n" );
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document.write( "That's 26*10*10*10 = 26000\r\n" );
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document.write( "Case 2. 1 letter followed by 4 digits.\r\n" );
document.write( "Annex a digit to each of the 26000 ways in Case 1.\r\n" );
document.write( "That can be done in 10 ways.\r\n" );
document.write( "That's 26000*10 = 260000\r\n" );
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document.write( "Grand total: 26000 + 260000 = 286000\r\n" );
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document.write( "---------------------------\r\n" );
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document.write( "Digits cannot repeat:\r\n" );
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document.write( "Case 1.  1 letter followed by 3 digits\r\n" );
document.write( "Choose the letter 26 ways.\r\n" );
document.write( "Choose the first digit 10 ways.\r\n" );
document.write( "Choose the second digit 9 ways.\r\n" );
document.write( "Choose the third digit 8 ways.\r\n" );
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document.write( "That's 26*10*9*8 = 18720\r\n" );
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document.write( "Case 2. 1 letter followed by 4 digits.\r\n" );
document.write( "Annex a fourth digit to each of the 18720 ways in Case 1.\r\n" );
document.write( "That can be done in 7 ways.\r\n" );
document.write( "That's 18720*7 = 131040\r\n" );
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document.write( "Grand total: 18720 + 131040 = 149760\r\n" );
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document.write( "Edwin
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